The present invention relates to a member for electroluminescent (EL, hereafter) devices for removing a predetermined gas component in an EL device and to an EL device containing the same.
EL devices have been conventionally used as a light emitter in a display or a light emitting element of various apparatuses such as mobile apparatuses. However, EL devices have a disadvantage that the luminous performance, such as luminance and luminous uniformity, substantially degrades with aging for certain period of time or under a high temperature. Such degradation in luminous performance has been found to be caused by non-luminous portions (dark spots) formed by the moisture adsorbed on the surface of the components and the constituting materials and by the moisture, oxygen, and organic gases introduced from the outside.
Thus, in order to eliminate the cause of the degradation in luminous performance (occurrence of the dark spots), an EL device has been proposed in JP-A-9-148066 (The term xe2x80x9cJP-Axe2x80x9d as used herein means an xe2x80x9cunexamined published Japanese patent applicationxe2x80x9d). The EL device comprises drying means which chemically adsorbs the moisture and is composed of a compound remaining solid even after the adsorption. The drying means is made by solidifying an appropriate compound and then fixed within the EL device.
However, the above-mentioned EL device needs the process of solidifying the compound for the drying means, and hence requires time and equipment for the solidification. This causes a problem of a higher production cost.
The present invention has been devised considering such a situation. An object of the present invention is to provide a member for EL devices reducing the cost of EL device production and an EL device containing the same.
In order to achieve the above-mentioned object, a first aspect of the present invention is a member for EL devices, comprising: a removing agent for removing a predetermined gas component; and an adhesion member fixed to the removing agent. And, a second aspect of the present invention is an EL device containing the member for EL devices.
That is, a member for EL devices of the present invention comprises: a removing agent for removing a predetermined gas component; and an adhesion member fixed to the removing agent and for adhering the removing agent onto the inner surface of an EL device. Because of this simple structure comprising a removing agent and an adhesion member, the member for EL devices permits easy fabrication thereof. Accordingly, the production cost of a member for EL devices is reduced, and so is the production cost of an EL device.
In case that a member for EL devices of the present invention comprises a sheet member having a gas permeable portion covering the removing agent, the removing agent can be covered between the sheet member and the adhesion member.
In case that the gas permeable portion of a member for EL devices of the present invention is composed of a porous material of polytetrafluoroethylene (PTFE, hereafter), because of the good heat resistance of this material, the EL device can be used stably even in a heating environment.
In case that the gas permeable portion of a member for EL devices of the present invention is composed of a porous material of a polymer having a crystal structure, the polymer having the crystal structure permits an easy control of the pore size of the porous material, thereby permitting an easy control of the performance of removing the predetermined gas component within the EL device.
In case that the gas permeable portion of a member for EL devices of the present invention is composed of a porous material of a thermoplastic resin, the good processability of the thermoplastic resin permits an easy processing of the gas permeable portion.
In case that the thermoplastic resin of a member for EL devices of the present invention is a polyolefin resin, the polyolefin resin permits an easy control of the pore size of the porous material, thereby permitting an easy control of the performance of removing the predetermined gas component within the EL device. Further, the low cost of the polyolefin resin reduces the production cost of the EL device. Furthermore, such a material is easily recyclable, and hence the amount of waste can be reduced by recycling after the use.
In case that the adhesion member of a member for EL devices of the present invention has the modulus of elasticity within the range of from 1xc3x97103 to 1xc3x971010 Pa at 25xc2x0 C., because of the sufficient flexibility, the adhesion is also sufficient within the temperature range in which the EL device is used.
In case that a member for EL devices of the present invention has the modulus of elasticity of 1 MPa or higher at 25xc2x0 C., because of the sufficient rigidity of the member for EL devices, the workability during the fixing of the member for EL devices increases, which permits the automated production of the EL devices. In particular, the modulus of elasticity is preferably set to be within the range of from 1 MPa to 1xc3x97106 MPa for a substantial improvement of the workability. However, this upper limit of modulus of elasticity is an example and not restrictive.
From the viewpoint of handling and the like, a member for EL devices of the present invention has a thickness of 5 mm or less, preferably within the range of from 5 xcexcm to 5 mm, more preferably within the range of from 50 xcexcm to 3 mm. However, these lower limits of thickness are examples and not restrictive.
In an EL device using a member for EL devices of the present invention, the member for EL devices has a simple structure comprising a removing agent and an adhesion member, and hence can be easily adhered onto the inner surface of the EL device, thereby reducing the production cost of the EL device.